Maven vs. Gradle vs. Ant

Which is the best build tool? We find out where Gradle, Ant and Maven experts, think they have an edge over the competition.

Which is the best build tool? In part two of our interactive
build tool comparison, we find out where the three of the major
build systems – Ant, Maven and Gradle – have an edge over the
competition. And don’t forget to send us your questions, because in
part four we’ll be putting your questions to our three experts.
Questions can be sent via email, or posted in the comments section
at the bottom of the article.

JAXenter: In your opinion, what are your build
tool’s strengths, compared to other build systems

Hans Dockter (Gradle): Gradle offers many
features that make every-day build processes easier. These include
a generic function to skip certain Aspects of a build, without the
aid of a Build-Master. In Ant, the developer has to use Skip
Properties to miss out build Aspects; in Maven he needs to adjust
the plugins – if this is possible.

Gradle also offers our beloved Camel Task Execution for
abbreviating task names when running in the console. This results
in a very dynamic output, which includes a counter for the executed
tests. There is a ‘stand alone’ GUI, which can be accessed with
gradle-gui. There is a wrapper for building projects with Gradle,
without even installing Gradle. This wrapper also means
zero-administration of client-centric Gradle-installations in the
enterprise. I could go on!

The original motto of Gradle was: “Make the impossible possible,
make the possible easy and make the easy elegant.” This motto
summarises the contrasting characteristics of Gradle, and Ant and
Maven:

Ant

Ant is a pure, imperative build system, which means Ant has the
flexibility to make the impossible possible. However, often Ant
doesn’t make development easy and elegant, which frequently results
in builds that are difficult to maintain and extend. Ant lacks the
declarative element and the conventions. Ant does not model the
problem space. The Ant-model consists of Task, Target, Project,
Resources and Properties. It does not understand source
directories, project dependencies, etc. … This, the user has to
model himself – and with the limited language elements that Ant
provides. Gradle offers a rich, extensible model to model software
projects – without losing the flexibility of Ant. This flexibility
can be accessed when you need it; otherwise, it rests in the
background of the declarative build description.

We consider Ant not primarily as a competitive build system, but
as ageing friend and helper. This is especially true when it comes
to the treasure of existing Ant tasks. These are First Class
Citizens in Gradle. You can also easily wrap them in a
Gradle-plugin, and get Convention over Configuration. You can load
an Ant-build in Gradle-runtime and integrate it with Gradle. You
can define dependencies of Gradle tasks to Ant targets and vice
versa. You can also extend Ant targets in Gradle. This way you can
very gently migrate – in whole or in part – from Ant to Gradle.

Maven

Even if a number of requirements can be easily realised with
Maven, far too often it’s very difficult to solve relatively easy
problems with Maven. Project Automation is an important and
critical component of successful software development but
frequently we keep encountering things that are not automated,
because it is too difficult to integrate with the build systems in
use. This particularly applies to the requirements which cannot be
anticipated by the build system. The implementation of such
requirements often require workarounds, which result in high
maintenance costs. I would also like to quote Erich Gamma:

“Frameworkitis is the disease where a framework wants to do too
much for you, or to do it in a way that you don’t want, but can’t
change. It’s fun to get all this functionality for free, but it
hurts when the free functionality gets in the way. But, you are
tied into that framework. To get the desired behaviour you start to
fight against the framework. And at this point you often start to
lose, because it’s difficult to bend the framework in a direction
that it didn’t anticipate. Toolkits do not attempt to take control
for you, and therefore they do not suffer from frameworkitis.”
Erich Gamma

This quotation corresponds to our intensive experience with
Maven, and we do not anticipate anything fundamentally changing
with Maven 3. This is not an issue with XML. Gradle follows the
path recommended by Erich Gamma and offers small, optional
frameworks based on toolkits.

Gradle extends the declarative approach of Maven, making it
suitable for the full range of company-specific requirements (see
above.)

Gradle offers very powerful support for multi-project builds.
Project dependencies are First Class Citizens, in contrast to
Maven, where dependencies are modelled in the same way as normal
external dependencies. This allows for many optimisations (eg,
partial builds,) and makes this information available to the users.
Gradle doesn’t use inheritance to define the common features of
sub-projects. Instead, there is ‘configuration injection’ where a
user can inject shared configurations into any group of
subprojects. The Maven Mix In functionality for poms (which is
postponed until Maven 3.1) is heading in the same direction, but is
not as powerful.

There is one final aspect that often leads to considerable
debate. Many Maven users like the very restrictive, unchangeable
Presettings of Maven. In their opinion, they result in builds that
are easy to understand, and easy to maintain. We believe that the
opposite is often the case. What happens when you have to squeeze
complex requirements into a simplified model? First, it is
laborious. Often, it is so complex that it cannot be done. The
result: the build rests as it is. Congratulations ;) But, what
happens when you squeeze? Then, it often begins to become
‘offensive’ (in the words of Kent Beck.) You have to tear apart
what belongs together (Shotgun Surgery,) or you get unnecessary
indirections (such as Lazy Project.) The worst thing is that the
developer is forced to violate a fundamental principle of
domain-driven design: you have to make explicit the implicit. Such
a build may at first glance look simple, but in reality it is often
a maintainability monster.

We believe that it is important to have a clearly structured
process for the build within an organisation. Gradle supports this
more than any other build tool that we know of. But, the
organisation must be able to create these processes themselves.
Gradle offers a set of standard processes, but these are not
privileged, and they are extensible. You can also design your own
processes or use a mix.

Matthew McCullough (Maven) : Maven’s unique
strengths lie first and foremost in its opinionated conventions,
proven to be industry-desired through an eight-year track record.
Build scripts are, in most cases, not where developers should be
expressing most of their creativity. Technical prowess should be
demonstrated through the coding of the software product itself.
Maven facilitates spending less developer time with the build
script than other build tools because the build for multiple
systems can derive the majority of their configuration from a
parent script through true object-oriented inheritance.

I’ve seen far too many scripts in my day that, because there
were few if any bounds placed on the build script by the build
tool, were a cacophony of small elements rather than a symphony of
plugins, run in a predictable lifecycle sequence. My No Fluff Just
Stuff colleague, David Bock, recently extolled via Neal Ford at
RailsConf 2010, that “constraints can be liberating” and I believe
that Maven strongly embraces that sentiment.

Additionally, Maven aims through project object model
inheritance (as discussed above) and through archetypes (powerful
interactive project templates) to reduce the occurrence of
construction of build scripts through the error prone practice of
copy-and-paste coding. There are over 100 archetypes in the central
repository today, all accessible through a natural dialogue with
Maven. Each archetype prompts for the Java package and project name
and instantiates a quality project, ready to be checked in to
version control and accept new source code from developers. This
mitigates the embarrassment of copy-and-pasting a new project’s
build script and accidentally forgetting to rename all the
occurrences of “Blue Customer” for the new “Red Customer” project
until it shows up on a projector screen during the first internal
demo.

Lastly, Maven is the creator and keeper of the canonical
dependency repository format. Ant Ivy, Gant, Gradle, and even the
upcoming Grails dependency management systems all follow and
leverage the repository layout and centralization of artifacts that
Maven provides. It is an acknowledgement that there is eight years
of value stored at http://repo1.apache.org/maven2 that will likely live
on in both Maven as well as other build tools for many years to
come.

Jan Matèrne (Ant) : Flexibility and openness.
Personally, I prefer reading a piece of code and immediately
understanding what is being done. I like to go through the code
step by step and understand it from start to finish. With systems
that do everything internally, out of sight of the developer,
everything seems to be done by “magic.” But when something does go
wrong, you don’t know how to solve it.

Also, with Ant it is possible to customise a build according to
a project’s particular circumstances and needs, with only minor
changes.

Agree? Disagree? Don’t forget to send us your comments
and questions, and stay tuned for part three!

Matthew McCullough is an energetic 14 year veteran of enterprise software development, open source education, and co-founder of Ambient Ideas, LLC, a Denver consultancy. Matthew is currently a member of the JCP, reviewer for technology publishers including O’Reilly, author of the upcoming ‘Presentation Patterns & Anti-Patterns’ book, multi-year speaker on the No Fluff Just Stuff tour, author of the DZone Maven, Git and Google App Engine RefCards. He channels his teaching energy through activities as President of the Denver Open Source Users Group. His experience includes successful JEE, SOA, and Web Service implementations for real estate, finance and telecommunications firms in addition to publishing several open source libraries. Matthew jumps at opportunities to mentor and educate teams on how to leverage open source. His current topics of R&D are Cloud Computing, Service Integrations, Maven, Git, and Hadoop.

Jan Matèrne

Jan Matèrne is a software developer in the computer centre of the financial NRW. His interests lie in build automation and code generation. He has worked with Ant since 2000, has been a committer since 2003, and since 2004 he has been a member of the PMC. Outside of Ant, he is active in the Hudson and Args4J projects.

Hans Dockter

Hans Dockter is the founder and director of Gradle and the CEO of Gradle Inc. He has 12 years experience as a software developer, project manager, architect, trainer and mentor. In olden times, he was also a committer for the JBoss project and created the JBoss-IDE.